According to available information, the suburbs from Bandra to Mira Road (Thane) on the western side and large swathes of areas on the eastern side were hit by the snapping of power supply.
The blackout, which also hit sections of the Chhatrapati Shivaji International Airport, is attributed by officials to a supply grid problem.
An airport official said that back-up power was activated to maintain essential services like x-ray screening and runway lights.
There was no immediate impact of the power failure on flight operations, he said.
The power breakdown inconvenienced thousands of people living in tall buildings, where the elevator operations were hit.
The power failure also slowed down the evening north-bound traffic as street lights and highway lights went off.
There have been no reports of any untoward incident on account of the power failure.